Need some help on understanding the function of ratio. I change the ratio but don't see a resulting change in the data. (sometimes yes sometimes no) have seen this using both the original v3 of the SW and the new EKM Dash.

With the Pulse Input meter (25EDSP-N in your case) you can set the pulse input ratio to anything from 1:1 to 9999:1. This is so if you have something that pulses really fast, the counter will not go too high too quickly. If you have the pulse input ratio set to 1000:1 (the default setting) it will take 1000 pulses for the counter to increment 1.

If you have a pulse count of 23 and you change the pulse input ratio from 1000:1 to 1:1 the pulse count will still be 23. (that is until the meter counts some pulses and starts to increment.